1. Field of the Invention
The present invention relates to an interchangeable lens, to a camera body, and to a camera system.
2. Description of Related Art
Generally, with a camera system in which lenses can be interchanged, within each interchangeable lens, there is provided at least one drivable optical member whose driven state changes, and this may for example be a lens for focus adjustment or the like. For various types of control, the camera body needs information related to the driven state of this type of driven member (i.e. related to the state to which the driven member is currently driven). For example, in the camera system described in Japanese Laid-Open Patent Publication Heisei 10-68871 (Patent Document #1), an encoder that monitors the movement of a lens shifting system is provided. A signal that monitors the amount by which the lens is driven is outputted by this encoder, and is fed back to a lens drive control CPU via lens side contact points provided upon a mounting portion of the lens and body side contact points provided on a mounting portion of the body, with the body side contact points corresponding to these lens side contact points. Moreover, with the camera system described in Patent Document #1, a main CPU within the camera body and a lens CPU within the photographic lens and so on are coupled together by other contact points, different from those that transmit the monitor signal described above. The main CPU receives information needed for controlling camera sequencing and exposure operation and so on from the other CPU and so on, and sends information needed for camera sequencing to the other CPU. In other words, these contact points are contact points for performing general purpose communication between the main CPU and the lens CPU.